Ultra-Thin Silicon-Based Pressure and Temperature Sensors Integrated on a Flexible Neural Probe Array

This paper reports ultra-thin silicon-based pressure and temperature sensors integrated on a flexible neural probe array. The flexible probe array is fabricated through heterogeneous integration of doped polysilicon pressure/temperature sensors based on a$3 \mu ~\mathrm{m}$ultra-thin silicon substrate and SU-8 polymer. Compared to conventional multifunctional flexible probes where pressure- and temperature-sensitive materials are directly deposited on the polymer substrate, the proposed design exhibits significantly improved linearity and remains unaffected by deformation of the flexible polymer. The measured pressure sensitivity is$5.30 \mu ~\mathrm{V} / \text{kPa} / 3.3 ~\mathrm{V}$, and the temperature sensitivity is$56.1 \Omega /{ }^{\circ} \mathrm{C}$.